The present invention relates to a telephone including a controllable electromagnetic transducer which produces a variable sound level as a function of frequency, a method which permits of playing melodies on such a telephone, and a method of coding such melodies.
Telephones and notably mobile telephones require ringing tones which can be heard in a noisy environment. Moreover, these telephones are subjected to demanding constraints as regards to bulkiness (weight, volume) and supply voltage. To comply with all these constraints, one is led to use electromagnetic transducers (or buzzers) in such telephones, which transducers are provided for generating one-tone ringing sounds (or beeps) of a high sound level. By way of example, the frequency response of such an electromechanic transducer is shown in FIG. 2. This frequency response is very irregular, but a sound level of about 95 dB is obtained for a frequency of 2.703 kHz.
For improving the ease of use of de telephones, various musical melodies are proposed to the user so as to replace these conventional ringing sounds. For this purpose, U.S. Pat. No. 4,480,153 proposes the use of a musical apparatus which is connected to the telephone to play various musical melodies.